Emergency slack take-up device



July y2, 1935. E. R. EVANS E -r A1.

EMERGENCY SLACK TAKE-UP DEVICE u 5 Sheets-Sheet 1 Filed April 23, 1932 aon 641066,42 a 72 July 2, 1935. E. R. l-:vANs ET Al. 2,006,634

EMERGENCY SLACK TAKE-UP DEVICE' mea April 2s, 1952 s sheets-sheet 2 g17a' J70 174 08 5J@ ['awm/ 2. wma Edward @www July 2, 1935. E; R, EVANSEr AL l 2,006,634

EMERGENCY SLACK TAKE-UP DEVICE 'Filed April 23, 1932 3 Sheets-Sheet 5 l@www E@ Patented July 2, 1935 PATENT OFFICE 2,006,634 EMERGENCY sLAcxTAKE-UP DEVICE Edwin R. Evans and Edward A. Rockwell, Chicago, Ill.

Application April 23,1932, Serial No. 607,039

18 Claims.

The present invention relates to emergency lever slack take-up devicesfor applying the Wheel brakes of a motor vehicle.

With the development of power brake systems v particularly thoseincluding mechanical power in spite of considerable Wear of the brakelinings.

In our application, Serial No. 571,050, filed October 26, 1931, we havedisclosed a slack takeup link between the brake lever which is actuatedby the power brake and the emergency lever whereby, when the brakes areapplied through operation of the power brake and the brake linkage movedto a sufiicient extent, the slack take-up link will move to take up theslack in the linkage between the emergency lever and the brake lever.Therefore in this system the slack in the emergency lever controllinkage is automaticallytaken up after a certain amount of wear of thebrake linings and the emergency.

lever is always available for fully applying the wheel brakes.

Itis an object o'f the present invention to provide an emergency leverslack take-up device which may be manually operated through back andforth movement of the emergency Alever in order to take up all the slackin the linkage and fully apply the` wheel brakes.

It is further ani object of the invention to employ pawl and ratchetmeans for holding the linkage against retractive movement while theemergency lever is being operated for applying the brakes and toassociate with the emergency lever, mechanism for releasing the pawl andratchet means to permit release of the wheel brakes.

Further and additional objects and advantages of thev present inventionwill be more readily apparent from the following description taken inconnection with the attached drawings, in which Figure l is a sideelevation partially in section of an emergency slack take-up device inreleased position; e

Figure 2 is a detail section of a portion of the device shown in Figure1;

Figure 3 is an enlarged section of the cylinder and piston in Figure 1showing the parts in releasing position;

Figure 4 is a side elevation of a modified arrangement;

vber, 34 and a pressure chamber 36.

Figure 5 is a side elevation of a further modication;

Figure 6 is an elevation partially in section of the device shown inFigure 5;

Figure 7 is a detail section of the device shown 5 in Figure 5;

Figure 8 is a side elevation of a power brakev unit showing theemergency lever and slack take-up device of Figure 6, and

Figure 9 is a plan view partially in section of the structure shown inFigure l.

In Figures l, 2 and 3 there is shown an arrangement including anemergency brake lever I0 carried by pivot pin l2 and having a handle I4.The handle carries a movable button I6 for operating a-release rod l1which is guided for reciprocable movement by an enlargement I8 on thehub .of the lever I0. The lever may be the usual brake lever in thebrake linkage of the motor vehicle which is suitably connected to thewheel brakes of the vehicle and during normalv braking is operated bythe brake pedal of the vehicle and preferably through a power brake. Thelever 20 at its upper end carries a pivot pin 22 forming a pivotalconnection for 25 a pair of rods 24-24 having slotted ends 26 forengaging the pivot pin 22. The slotted ends 25 permit movement of thebrake lever 20 during normal braking of the vehicle without movement ofthe rods 24.

At their left-hand ends, the rods 24 are threaded into a cylinder headmember 28which has secured thereto a fluid cylinder 30 having av fluidreservoir chamber 32, a pumping cham- A piston 33 is slidable within thecylinder 30 and forms a movable wall of the pressure chamber 36. Thepiston 38 has mounted therein a sleeve 40 carry- .ing at its inner end avalve disk member 42 for controlling the vflow of fluid from thereservoir chamber 32 through the valve passages 44 and 46 into thepumping chamber 34. The sleeve has a plurality of openings 48 for apurpose to be later described.

The valve disk 42 together with ythe sleeve 40 is moved to normal seatedposition upon the valve seat 50 which is rigid with the piston 38 by aspiral spring 52 which reacts at its righthand end against an abutment515 vsecured to the end of a valve stem 56. The valve stem 56 carries atits left-hand end a valve member 58 adapted to cooperate with a valveseat 60 formed on the piston 38. Slidable within the sleeve 40 is asecond sleeve 62 which, in normal released position, covers the openings.4.8 in the sleeve 55' 40. The valve stem 56 carries a pin 64 adapted toengage projections 66 formed on the sleeve 62. The sleeve 62 is pressedfor movement in a right-hand direction by a. spring 68 between lugs 10at the left-handend of sleeve 62 and the inner surface of the valve 58.The piston 38 is secured to a tubular member 12 which has reciprocabletherein a piston 14 forming a movable wall of the pumping chamber 34.The cylinder head 28 together with the cylinder 30 lis normally heldagainst an abutment member 16 which receives the right-handend of thetubular member 12 and forms an abutment therefor. through a shoulder 18.

The release rod I1 carried by the emergency lever I0 has a projection 80.at its lower end adapted to engage a contact face 82 formed on themember 16. The piston 14 which extends through the member 16 has ayoke-shaped righthand end 84 secured by pin 85 to the lower end of leverI0. A yoke-shaped extension 86 from abutment 16 has on opposite sidesratchet'teeth 88 adapted to be engaged by the arms 90 of a U-shaped pawl9| having Wing-shaped extensions 92. The pawl 9| is mounted in a bracket94 xedly secured by bolts 96 to some xed part of the chassis frame ofthe vehicle. The bracket 94 contains therein a spring 98 normally urgingthe pawl 9| in an upward direction. The bracket 94 also serves to mounta pair of pawls |00 on each side thereof, upwardly pressed by springs|02. The pawls |00 are adapted to engage ratchet teeth |03 on theunderside of rods 24. The ratchet teeth |03 on rods |04 are'formedsimilar in shape to the ratchet teeth 88 on the yokeshaped extension 86from the abutment 16.

When it is desired to apply the brakes through movement of the emergencylever I0, the lever is pulled back by the handle I4 and rotates in aclockwise direction -about the-axis of pivot pin I2. The engagement ofprojection with abutment face 82 of member 16 serves tornove the member16 in a left-hand direction and the arms of pawl 9| will successivelyengage the ratchet teeth 88 upon the yoke-shaped extension 86 of themember 16 to hold the member 16 against return movement. At the sametime the cylinder head 28, together with cylinder 30 will be moved in aleft-hand direction by the member 16 thereby moving the rods 24 andactuatng the brake lever 20. The pawls |00 will successively engage theratchetw teeth on .the rods 24 and prevent return movement. If the fullmovement of the lever I0 is insuilicient to fully apply the wheelbrakes, the lever is pushed ing iluid from the reservoir 32 into thepump ing chamber 34 by opening inlet valve 42. The lever I0 is againmoved in the opposite direction and movement of the piston 14 in aleft-hand direction will discharge 'the fluid from pumping chamber 34into the pressure chamber 36 by opening valve 58. It will be quiteobvious that -successive reciprocations of the lever- I0 will build up auid pressure in chamber36 and the uid pressure will nally becomesufficient to move the cylinder 30 together with cylinder .pressurechamber.

head 28 and rods 24 in a left-hand direction I while the piston 38,tubular member 12 and the abutment member 16 remain in stationarypositions. ciently to fully apply the wheel brakes by the hydraulicpressure which has been built up.

When it is desired to release the brakes, the button I6 is pusheddownwardly and at the same time the operator pulls back on lever I0. Theprojection 80 on rod` I 1 will rdisengage from abutment 82 and themovement of-v lever. I0 in a clockwise direction about its pivot I2 willthen be suflicient to bring the piston 14 into engagement with the endof the valve stem 56 and, as shown in Figure 3, will move the valve stem56 sufficient to permit fluid to flow back from the At th( same time pin64 on valve stem 56 moves the sleeve 62 and the openings 48 in sleeve 40will be uncovered to permit the fluid to return to the reservoir 32. InFigure 3 the spring 52 is shown as entirely compressed. The downwardmovement of rod I1 will also cause the lower end |04 thereof to engagethe arm 92 of pawl 9| and move it to released position. also causerelease of the pawls |00 since the arms 90 engage shoulders |06 formedon the pawls |00, as shown in Figure 2. With the lever |0 pulled back ina clockwise direction about its pivot to cause opening of the valve 58as in Figure 3 the fluid may return from the pressure chamber 36 to thereservoir 32. As the uid pressure is relieved the cylinder 30 togetherwith the rods 24 will move in a right-hand direction and permit releaseof the slack taken up in the brake linkage. After the cylinder 30 hasmoved into engagement with the abutment 16, all the slack taken up hasbeen released. Thereupon, by pushing back'the lever I0 to itsfullreleased position, as in Figure l, the abutment 16 together with thecylinder 30 moves in a right-hand direction to fully release the brakelinkageto the extent of the normal travel of the lever lII). The linkagewill therefore return to its normal inoperative position as the lever I0is allowed to return to its normal position and nally the pressure uponbutton I6 is released thereby returning-the rod |1to its normal positionwith the projection 80 engaging with the abutment 82 on member 16. Theconstruction is such that -if the normal movement of the lever I0 in a Amodication of the emergency slack take-up device is illustrated inFigure 4. In this arrangement the emergency lever I|0 carried by pivot||2 actuates a brake lever ||4 through a conlnecting link I|6, which hasa slotted opening ||8 receiving pivot pin |20 carried by the brake Therelease of pawl 9| will Thus the brake lever will be moved sufl'i- Ilever ||4. The link ||6also has a'slotted openf ing I I1 receiving andslidably supporting the link on the pivot pin I|2.v V The connectinglink ||6 has ratchet teeth |22 on its upper side and ratchet teeth |24on its lower side. The lever |0 carries pivots |26 and 28 above andbelow the connecting link ||6. Arpawl member |30 is carried by pivot |26and has atooth-shaped end |32 for engaging the ratchet teeth |22. Asimilar pawl member |34, having a tooth-shaped end |36 is carried bypivot |28. The pawl members are urged into engagement with the ratchetteeth |22- |24 bya tension spring |38 connecting the ends of the pawlmembers.

A bell crank lever |40 is carried by. pivot |26 and is operated by a rod|42. The depending arm of the bell crank lever |40 carries a pin |43which engages the loop portion |44 of a leaf spring member |46, the endsof which are bent to bear against the pawl members |30-I34 adjacent thepivots |28|28 therefor. It will be understood however that operation ofthe rod |42 will move the bell crank lever |40 in a manner to move thespring |46 in a right-hand direction so that the ends of the spring |46bear against thelug portions |48 and |50 of the pawl members, in whichposition the spring |46 will oppose the effect of the tension spring |38and tend to 'separate the pawl members.

In operation of the device illustrated in Figure 4, reciprocation of thelever ||0 will progressively move the connecting link ||6 in a manner tooperate the brake lever ||4. Thus movement of the lever ||0 in acounter-clockwise direction about the pivot |l2 from the position shownin Figure 4 will move the link ||6 through the action of pawl |34.initial movement of lever ||0 is insufficient to fully apply the brakesit is pushed back in a clockwise direction about pivot ||2 and the link||6 will be further moved through the action of pawl |30. Thesesuccessive movements may be continued until the brakes are sucientlyapplied.

The link 6 Will be held against backward movement by the engagement ofthe respective pawl members |30 and |34 with the ratchet teeth |22 and|24 thereon. When the operator desires to release the brakes, it is onlynecessary to operate the rod |42 in a manner to move the spring |46 asabove described, whereupon by reciprocation of the lever ||0, the brakesmay -be fully released and the slack taken up is entirely let out.

In Figures 5, 6 and 7 a still further modication is illustrated. 'Iheemergency lever |60 is rotatably supported on pivot pin |62 which isrotatably carried in a fixed boss |64 and keyed against displacementtherefrom by a pin |66 engaging a groove |68 in the pin |62. Secured tothe pin, |62 by a key |69 and positioned between the hub |10 of lever|60 and the outer face on the bearing boss |64 is a lever arm |12 whichcarries a pivot pin |14 for connecting a rod |16 extendingto a suitablebrake operating lever. The hub |10 of lever 60 has internal ratchetteeth |18. yA plurality of rollers |80 are mounted between the ratchetteeth |18 and the cylindrical surface of pin |62 and in acounterclockwise direction of movement of lever the rollers will begripped and the pin |62 and arm |12 will move therewith. 4Movement oflever |60 in a clockwise direction will not tend to transmit anymovement to pivot pin |62. In order to hold the lever arm |12 in theposition to which it has been moved by operation of lever |60, the leverarm 12 has integrally formed thereon an enlargement |82 slida-blysupporting a pawl member |84 urged by spring |86 into engagement withthe ratchet `teeth |88 of a fixed sector |90. A ring-shaped member |92closes the space between hub |10 of the lever |60 and ,the outer end |94of pivot pin |62 and the ring member |92 carries finger". |96 whichextend into the narrowed portions of the spaces between the pivot pin|62 and the ratchet teeth |18. The ring |92 also supports a plurality ofspring mem- If theA bers |98 which are positioned on the opposite sidesof the rollers |80 from the ngers |96. Carried by pivot pin 200 which isfixed to the hub |10 of the lever |60 is a pivoted link 202 which has anopening 204 normally concentric with the axis of the pin |62 andreceiving 'the end 206 of a bent rod 208, the other end pin |62whereupon the lever arm |12 will be moved to actuate the brakes throughbrake rod |16. If the initial movement of the lever |60 is insufficientto fully apply the brakes, it is pushed back in a clockwise directionduring which movement the brake linkage will be held in partiallyapplied position by the pawl and ratchet mechanism. The lever |60 isagain moved in a counter-clockwise direction thereby producing furthermovement of the brake linkage. Successive movements of the lever |60 incounter-clockwise directions Will nallyproduce full apl lication of thewheel brakes. When it is desired to release the brakes, the rod 2|6 is,'moved in a downward direction thereby turning link 202 in a clockwisedirection about the pivot pin 200 and moving the rod 208 in such amanner as to first release the pawl |84. further movement of rod 2|6 thepin 2|8 is moved to rotate the ring |92 in a direction to force therollers '|80 out of gripping'engagement between the pin |62 and the hub|10 of lever |60. The brakes are therefore allowed to fully release andthe lever |60 may be returned to its normal inoperative position.

Figure 8 illustrates the manner in which the slack take-up device,illustrated in Figures 5, 6 and 7, may be associated with the powerbraking linkage of a motor vehicle. The usual foot pedal 230, is pivotedat 232 and connected by the pull rod 234 to the input lever arm 236 ofthe powerl brake unit, which is enclosed in casing 238. vIt is to beunderstood that the power brake unit is operative to amplify thepressure received in movement of the input lever arm through therotation of the propeller shaft 240 and to transmit the amplified forceby rotation 0f the output rock shaft 242 to the double arm Ibrake lever244. The power brake unit may `,have a construction such as illustratedin Rockwell, et al. Patent No. 1,896,377, issued February 7, 1933. I'hebrake lever 244 is connected at its lower end to the forwardly extendingpull rod 246 for actuation of the front, wheel brakes and is connectedat its upper end to the rearwardly extending pull rod 248 for operationof the rear wheel brakes. The rod |16 has attached thereto a clevis 250having a slot 252 for receiving the pivot pin 254 carried by the brakelever 244.

It will be understood that upon normal brake actuation the pedal 230will be depressed thereby bringing the power brake unit into action andproducing clockwise rotation of the output rock shaft 242 and movementof the brake lever 244 in a direction to actuate the front and rear,

will slide in the slot 252. However, if it is desired tb actuate thewheel brakes by the emergency lever |60, the wheel brakes may be fullyapplied even though the total movement of the lever |60 in an applyingdirection is insufilcient to fully take up the slack. Thus,counterclockwise movement of the lever |60 will partially apply thebrakes and the pawl |84 engaging the ratchet teeth |88 will hold thebrake linkage While the lever |60 is returned to normal position forfurther application of the 'brakes upon again moving in acounter-clockwise direction. Thus a high vleverage is .obtained by thehand or emergency brake control and the required travel is obtained bythe back-and-forth movement.

YWe claim:

1. In a brake linkage, a brake actuating member, a pivoted emergencylever, means normally holding said brake actuating member againstmovement in a direction for release of the brakes, means operative bythe emergency lever through back and forth movement thereof for movingsaid f brake actuating member in a` direction for application of thebrakes and means operative from a point adjacent the han'- dle of theemergency lever for releasing said holding means.

2. In a brake linkage, a brake actuating lever, a pivoted emergencylever and fluid pumping means operated by movement of said emergencylever for moving saidbrake lever in a direction to apply the brakes.

3. In a brake linkage, abrake applying lever, a pivoted emergency lever,means operative directly. by said emergency lever through movement inone direction for moving said brake lever in a directionl to apply thebrakes and means operative by continued movement of said emergency leverin back and forth directions for further moving said brake lever in adirection to apply the brakes.

4. In a brake linkage, a brake applying lever, a pivoted emergencylever, means operative by movement of said emergency lever in onedirection for directly moving said brake lever in a direction to applythe brakes and fluid pumping means operative by continued movement of'said emergency lever in back and forth directions for further movingsaid brake lever in a direction to apply the brakes.

5. In a brake linkage, a brake applying lever, a pivoted emergencylever, a link pivotally connected to said brake applying lever, pawl andratchet means for holding said link 'against movement in a direction forrelease of the brakes, a cylinder secured to said link, a piston in saidVcylinder and means operative through movement of said emergency leverfor pumping iiuid past the head of said piston to develop fluid pressurewithin said cylinder for moving said brake applying lever in a directionto apply the brakes.

6. In a brake linkage, a brake applying lever, a link pivotallyconnected to said brake applying lever, a cylinder carried by said link,pawl and ratchet means for holding said link against retractivemovement, a piston in said cylinder, an abutment member fixed withrespect to said piston and positioned adjacent the head of saidcylinder, pawl and ratchet means for holding said abutment memberaganstretractive move- .ment, a pivoted emergency lever, means movable ber andtransmit movement to said cylinder, whereby said brake applying lever ismoved in adirection for application of the brakes and means operated bycontinued back and forth movement of said emergency lever for developingfluid pressure beyond the head of the piston in said cylinder for movingsaid cylinder relative to said abutmentrmember for further applicationof the brake applying lever.

7. In a brake linkage, a brake applying lever, a link pivotallyconnected to said brake applying lever, a cylinder secured to said link,pawl and ratchet means for holding said link against retractivemovement, an abutment member adjacent the head of said cylinder, apiston head Within said cylinder in xed relation with respect to saidabutment member, said cylinder having a fluid reserve chamber on oneside of,

the piston head and a fluid pressure chamber on the other sidev of thepiston head, a valve controlled pumping chamber in communication withsaid fluid reserve chamber and said iluid pressure chamber, a pistonforming a movable wall of said pumping chamber, a pivoted emergencylever, a connection between the piston cooperating with the pumpingchamber and a depending arm of said emergency lever, a release rodcarried by said emergency lever having a projection adapted to engagesaid abutment member whereby movement of said emergency lever in onedirection first transmits applying movement to said abutment member andto said cylinder and said emergency lever being operative by continuedback and 'forth movement to deliver fluid from said reserve chamber tosaid lpressure chamber, whereby said cylinder is further moved inapplying direction relative to said abutment member,said release rodbeing movable. to render the pawl and ratchet meansinoperative to permitrelease of the brakes.

8. In a brake linkage, a brake applying lever, a pivoted emergencylever, a link pivotally connected to .said brake applying lever, saidlinkv having ratchet teeth on the upper and lower sides thereof, apairof pawl members pivotally carried by said emergency lever above andbelow the pivot for said emergency lever and adapted to engage theratchet teeth on the upper and lower sides of said link, resilient meansnormally holding said pawls in engagement with said ratchet vteethwhereby said emergency lever,

through back and forth movement thereof, will move said link in anapplying direction and means carried by said emergency lever forrendering the pawl members inoperative to permit the release of thebrakes.

9. In a brake linkage, a brake applying lever, a pivoted emergencylever, a link pivotally connected to the brake applying lever, said ofsaid first-mentioned resilient means to render said paw1 membersinoperable, whereby the brakes may be released.

1o. In a brake linkage, a pivoted brake gpply- 75 means for rotatingsaid brake applying arm in one direction only through movement of saidemergency lever.

11. In a brake linkage, a pivoted brake applying arm, a brake rodpivotally connected to said arm, a xed sector having ratchet teeththereon, a pawl member movably carried by said arm, resilient means fornormally holding said pawl member in engagement with said ratchet teethto prevent retractive movement of said brake applying arm, an emergencylever with said brake apmovement of said emergency lever in onedirection only for moving said brake applying arm and releasing meanscarried by said emergency lever for moving said pawl to inoperableposition to permit release of the brakes.

12. In a brake linkage for motor vehicles, a`

pedal-controlled brake actuating system, an emergency lever, meansconnecting the emergency lever to the pedal-controlled brake system andmeans associated with said emergency lever for obtaining suflicienttravel to fullyl apply the brakes through back-and-forth movements ofthe emergencylever.

13. vIn a brake linkage for-motor vehicles, a

power brake actuating system, a pedal for conthe operation of the powerbraking a pivoted emergency lever, means controlling system,

necting the emergency-lever to the power braking system for independentcontrol of the brakes and means for obtaining sufficient travel to fullyapply the brakes through back-and-forth movement of the emergency lever.Y

14.^In a brake system for motor vehicles, a powerbrake, a double armbrake lever operative from the output of said power brake and connectedto the wheel brakes, a pivoted emergency lever, a link member' betweensaid emergency having a lost motion connection with said brake lever,pawl and ratchetmeans for holding said link member against retractivemovement as it is moved in a direction to apply the brakes and means forprogressively moving said link member in a direction for application ofthe brakes through back-and-forth movement of said emergency lever.

l5. In a braking system for motor vehicles, a pedal, 'a power brake;means for actuating said power ,brake through movement' of said pedal, abrake lever connected to the wheel brakes operated from the output ofsaid power brake, a pivoted emergency lever, means connecting saidemergency lever to said brake lever for operation of the wheel brakesindependent of the power brake, said means being connected with aleverage suiciently high to obtain the 'desired degree of brakingpressure and means for obtaining sufcient travel to fully apply thebrakes through back-and-forth movement of the emergency lever.

16. In a brake linkage, a brake actuating member, a pivoted hand brakelever, means'normally holding said brake actuating member againstmovement in a direction for'release of thebrakes, means operative toapply the brakes upon initial movement of the hand lever in onedirection and means operative to further apply the brakes upon returnmovement of the hand lever in the opposite direction.

17. In a brake linkage, a brake actuating member, a cylinderconnected'to said brake actuating member, a piston head in saidcylinder, a hand brake lever and fluid pumpingmeans operative throughmovement of said hand brake lever to build upluid pressure between saidcylinder and said piston head to produce movement' of said'brakeactuating member.

18. In a brake linkage, a brake actuating member, a vbrake applyinglever, means normallif eiectve to hold said brake actuating vmemberagainst movement in a direction for release of the brake, means operatedby the brake applying lever through movement in diflferent directionsthereof for moving said brake actuating member in a direction forapplication 'of the brake and means for vdisabling said hold- 'ing meansto permit release of the brake. lever and said brake lever, said linkmember

